Abstract:
We used to propagate clones of Betula pendula by grafting them during the winter months on seedlings of the same species. We produced our own understock by collecting our own seed. We planted them in a greenhouse at 65°F in flats with a mixture of perlite and peatmoss. The seedling was done during September or October.

The seeds usually germinate very rapidly and with a little help from liquid fertilizer they grow very well all winter long. About May, when the danger of frost is over, we pick them off into 2¼" rose clay pots into our regular potting soil consisting of sand and peat moss with Osmocote, and place them outside in a growing area. By fall, they are the thickness of a pencil. Only a few weeks before grafting we bring them in the greenhouse. The greenhouse temperature is maintained at 65°F and we used a modified veneer graft. This we find is the best way to produce understock because an unestablished understock is a sure failure in grafting birches.